In Granzow et al. U.S. patent application No. 448,450, filed Dec. 10, 1982 automated peritoneal dialysis apparatus is disclosed in which interconnecting flow conduits communicate with (1) a patient's catheter, (2) a container for warming dialysis solution, (3) a drain line, and (4) a source of dialysis solution. The flow conduit (4) which communicates with the source of dialysis solution defines a plurality of branching conduits having connectors on their respective ends, for communication with separate containers of dialysis solution. An improvement on this device is disclosed in Davis et al. U.S. Pat. No. 4,585,436 filed Nov. 3, 1983.
The disposable flow sets that are used with automated peritoneal dialysis apparatus carry interconnecting flow conduits connecting respectively to the four locations listed above.
The source of dialysis solution is generally a plurality of dialysis solution bags so that the flow conduit (4) connecting with the source of dialysis solution typically defines at least three branching conduits having connectors on their respective ends for communication with separate connectors of dialysis solution. This is needed because automated peritoneal dialysis typically utilizes large quantities of peritoneal dialysis solution.
Typical automated peritoneal dialysis solution modalities are continuous cycling peritoneal dialysis (CCPD) and intermittent peritoneal dialysis (IPD). In both of these modalities, multiple cycles are performed by automated peritoneal dialysis apparatus, in which an aliquot of peritoneal dialysis solution is placed into the patient's peritoneal cavity, and, after a dwell period, is drained. Following this, added cycles automatically take place, in which another aliquot of peritoneal dialysis solution passes into the patient's peritoneal cavity, followed by drainage after the predetermined dwell period.
Accordingly, the patient can spend his sleeping hours or other time undergoing automated peritoneal dialysis in which three, four, or more complete peritoneal dialysis cycles can take place in an automatic manner.
Often, added medication such as insulin is desirably administered to the patient through the peritoneal dialysis solution. However, with previous designs of flow sets for automated peritoneal dialysis, it has frequently been necessary to add a uniform amount of medication to each container of peritoneal dialysis solution which is connected to the flow set, since the flow rates through the respective branches of the prior art sets that connect with the peritoneal dialysis solution containers are not uniform. If one adds medication to only one of the peritoneal dialysis solution containers, the concentration of medication passing into the peritoneal cavity of the patient in the various cycles of solution administration tends to vary widely. In some of the cycles, the concentration of medication in the solution administered would be very low. In other cycles of operation, the solution concentration could be very high, because the prior art set tends to draw solution in a nonuniform manner from the respective containers of dialysis solution. Hence, one is forced to divide up the dose of medicine and to administer it to multiple containers of peritoneal dialysis solution. This is very inconvenient, and also increases the risk that the medicine is administered incorrectly, for example, in non-aseptic manner, or in a wrong dose.
In accordance with this invention, a flow set for automated peritoneal dialysis is provided in which it becomes possible to add supplemental medication to only one of the several peritoneal dialysis containers in use. Because the flow characteristics of the respective branches that connect to the peritoneal dialysis solution containers are more equal than in the prior art, one can rely upon the set to automatically mix the medication-loaded solution from one container in a predictable and constant manner with the solution from other containers, so that the patient receives a relatively constant dose at all times, or varying but predetermined and predictable pattern of dosage if that is desired.